function s1_generate_a_series_of_files(){
	for i in {1..100}; do
		echo $i > /tmp/new_file$i;
	done
}
function s2_list_4_files_in_long_format_about_account_and_group(){
	ls -l /etc/{passwd,shadow} |sort -d
}
function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/{passwd,shadow} |sort -d
}
function s4_find_items_related_to_given_group_name(){
	grep -h $1 /etc/{passwd,gshadow} |sort -d
}
function s5_create_group_for_given_group_names(){
	groupadd rnd && groupadd itoperation
}
function s6_create_users_and_set_their_group_as_required(){
	useradd -G rnd adam && useradd -G rnd bob && useradd -G itoperation calvin && useradd -G itoperation david &&useradd -G rnd edward
}
function s7_change_users_shell(){
	usermod -s /usr/bin/sn adam && usermod -s /usr/bin/sh edward
}
function s8_set_password_chage_policy(){
	passwd -n 10 -x 60 -w 10 adam
	passwd -n 10 -x 60 -w 10 bob
	passwd -n 10 -x 60 -w 10 david
	passwd -n 10 -x 60 -w 10 calvin
	passwd -n 10 -x 60 -w 10 edward
}
function s9_set_password_for_five_users(){
	usernames=("adma" "bob" "calvin" "david" "edward")
	for i in $(seq 1 5); do
	echo $(!i);
	echo $(( $i-1 ));
	done
	echo "${usernames[0]}:$1" | chpasswd
	echo "${usernames[1]}:$2" | chpasswd
	echo "${usernames[2]}:$3" | chpasswd
	echo "${usernames[3]}:$4" | chpasswd
	echo "${usernames[$(( $i-l  ))]}:$5" | chpasswd
}
function s10_lock_bobs_password(){
	sudo usermod --lock bob
}
function s11_include_adam_into_wheel_group(){
	usermod -a -G wheel adam
}
function s12_change_files_permission(){
	for i in {1..33};
	do
	chmod -R 640 /tmp/new_file$[3*i];
	done
}
